Level gauge devices, such as radar level gauges, are widely used in various applications, such as in process industry or for monitoring tanks for storing products. Generally, the level gauge systems are provided with electrical energy for operation through wires and communicate with a remote device, such as a host system, through wires. The wiring for an installation may be rather complex and costly, and flexibility may be limited. Therefore, field devices that do not require any wiring at all have become increasingly popular. Such a wireless level gauge system is configured to communicate with a remote device using a wireless communication protocol, for example wireless HART, and comprises a local energy store, such as a battery, for providing electrical energy for operation of the wireless level gauge system.
For wireless field devices in general, and wireless level gauge systems in particular it is, however, important to keep the average energy consumption low to avoid frequent maintenance for replacing batteries etc. This is particularly the case for radar level gauges that perform relatively complex measurement tasks. A radar level gauge propagates an electromagnetic transmit signal towards the surface of a product contained in a tank, receives an electromagnetic reflected signal being a reflection of the transmit signal at the surface of the product, and determines the filling level based on the time-of-flight of the electromagnetic transmit signal from the radar level gauge to the surface and back.
U.S. 2008/0278145 discloses a process measurement instrument adapted for wireless communication, which comprises a measurement unit, a wireless communication unit, arbitration logic and a common memory. The measurement unit and the wireless communication unit can independently write to and read from the common memory. In operation, the measurement unit and the wireless communication unit share information via the common memory, and the arbitration logic ensures that the wireless communication unit and the measurement unit are not active at the same time.
Although the solution according to U.S. 2008/0278145 provides for a low average energy consumption of a field device for wireless communication, it may be desirable to provide an alternative solution that may be simpler to implement and/or even more cost-efficient, at least for some applications.